Magnetic separator



1962 w. M. HOLT 3,021,951

MAGNETIC SEPARATOR Filed April 20, 1961 2 Sheets-Sheet 1 INV EN TOR.

WILLIAM M. HOLT BY Feb. 20, 1962 w. M. HOLT MAGNETIC SEPARATOR 2 Sheets-Sheet 2 Filed April 20, 1961 FIG- 2 o a." n

1 A ll INVENTOR.

WILLIAM M. HOLT Agen United States atent Cfiice 3,021,951 Patented Feb. 20, 1962 3,021,951 MAGNETIC SEPARATOR William M. Holt, Van Nuys, Caiif., assignor to Lockheed Aircraft Corporation, Burbank, Calif. Filed Apr. 20, 1961, Ser. No. 104,273 8 Claims. (Cl. 209--221) This invention relates to an apparatus for separating magnetic materials from a mixture of magnetic and nonmagnetic materials.

It is frequently desirable to separate magnetic materials from a mixture of magnetic and non-magnetic materials for purposes of reclamation or a separate processing of those materials. For example, ferrous ores or municipal refuse contain a substantial proportion of magnetic materials and it is highly desirable to separate these magnetic materials from the remainder of the mixture prior to disposal or processing.

Many types of magnetic separators have been devised but none of these in present use provide an acceptable degree of separation of the magnetic materials from the mixture and' none of the previous magnetic separators have been widely accepted. One type of previous magnetic separator utilizes a magnetic drum over which the material is passed and operated on the theory that the magnetic materials will cling to the drum and may be removed from the downwardly moving Side of the drum after other non-magnetic materials have been removed at a higher level. Another variation of this involves a conveyor belt passing over a magnetic pulley rotating on a horizontal axis which serves to allow non-magnetic materials to drop away as the belt moves downwardly around the drum carrying the magnetic materials to the underside then pulling them away by lateral movement of the belt to drop them into a receiving hopper. However, in either of these instances, when the mixtures of magnetic and non-magnetic materials are merely passed over the drum, the magnetic materials frequently never come in contact with the drum and are taken off the drum along with the non-magnetic materials. Also in this type of construction the magnetic field holds the magnetic material against the drum with non-magnetic materials thcrebetween so that they are carried to the hopper designed to collect magnetic materials.

The present invention contemplates a magnetic separator where any mixture of magnetic and non-magnetic materials is turned a plurality of times during the passage of the materials through a drum and the magnetic materials are effectively brought into contact with the inner periphery of the drum. Magnetic devices carried by the drum pick up these magnetic materials and efficiently separate them from the non-magnetic materials. The present invention may be broadly defined as an apparatus separating the magnetic materials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic tubular drum which is open at its opposite ends having support means for rotat-ably supporting the drum in an inclined position, means for rotating the drum around its longitudinal axis, means for feeding the mixture to the higher end of the drum including means to remove dust from the mixture, discharge conveyor means extending into the drum adjacent the downwardly moving side of the drum for substantially the entire length of the drum, a plurality of magnetic field producing means carried exteriorly to the drum in circumferentially space relation around the periphery of the drum, each of said magnetic field producing means being arranged to produce a separate magnetic field of the drum for attracting magnetic materials in the mixture in the drum and means for moving the magnetic field producing means away from the exterior periphery of the drum in a radial direction in the upper half of the downwardly moving side of the drum so that the attracted magnetic materials will be dropped onto the discharge conveyor means.

An important object of this invention is to provide an efiicient separation of magnetic materials from a mixture of magnetic and non-magnetic materials with minimum pollution of surrounding air.

Another object of this invention is to provide a magnetic separator wherein all of the materials directed through the separator are thoroughly turned and brought into contact with magnetic elements and efiiciently separate magnetic materials from the non-magnetic material in the mixture.

Another object of this invention is to provide a novel magnetic separator wherein a mixture of magnetic and non-magnetic materials is passed through the separator and wherein the magnetic field producing the elements of the separator are alternately held in close proximity to the magnetized materials and moved away from the magnetized materials so as to cause the magnetic materials to drop away in a desired location for conveying storage.

A further object of this invention is to provide a novel magnetic separator utilizing a hollow drum which is rotated While a mixture of magnetic and non-magnetic materials is passed therethrough and wherein the minimum power is required for rotating the drum.

A still further object of this invention is to provide a magnetic separator which is simple in construction and may be economically manufactured and which will have long service life.

Other advantages of the invention will become evident from the following detailed description which when read in conjunction with the accompanying drawings will illustrate my invention.

in the drawings:

FIGURE 1 is a side elevational view of an apparatus constructed in accordance with this invention.

FIGURE 2 is a sectional view taken along lines 2-2, FIGURE 1.

FIGURE 3 is an enlarged detail sectional view taken on lines 22, FIGURE 1.

FIGURE 4 is a sectional view taken on lines 4-4, FIGURE 3.

FIGURE 1 shows the magnetic separating apparatus including a drum 10, an elevator 11 and a dust collector 12. The mixture of magnetic and non-magnetic materials are elevated to the top of elevator 11 from any sort of a receiving mechanism at its bottom. The mixture is then discharged into a chute 15 which opens and dumps into the lower edge of the inlet end 16 of inclined drum 10. Drum 10 is open at both ends so as to accommodate the various apparatus extending into it from either end. Many mixtures of magnetic and non-magnetic materials contains a large amount of dust as would be experienced Where the mixture was municipal refuse. Because dust is an air pollutant, means must be provided to collect the dust before it is discharged into the surrounding air. A dust collector of the conventional vortex type 12 is provided opening into the upper side of chute 11 through the tubular pipe 18. Drum 10 rotates separating the magnetic materials and dropping them into the conveyor 20. The non-magnetic materials remain at the bottom of the rotating drum. The non-magnetic materials thus are discharged through chute 22 into waiting car 23 and the magnetic materials are discharged through chute 24 into waiting car 25.

The drum 10 is supported by structure 30 so that its inlet end 16 is higher than outlet end 17. Drive unit 32 rotates the drum continually during the separation operation. The drive unit 32 drives a spur gear 33 which meshes with a chain 34 surrounding the center of drum 10 providing for firm positive dn'ving traction. The drum is supported ateither end on rollers 35 mounted on the structure 3G.

The drum 10 is made of a non-magnetic material such as stainless steel. Circumferentially spaced around the exterior surface of the drum are a plurality of magnets 40. The magnetic materials will be attracted toward the magnets 40. As the drum rotates they will be carried up wardly to the top of the drum where the magnets will be moved away from the exterior surface to decrease the influence of the magnetic field on the magnetic materials so that they drop into the trough 42. Wall 43 of the trough 42 extends to a point adjacent the downwardly moving side of the drum it) so that wall 43 will scrape away any magnetic material which persists in clinging to the interior surface of drum 10. Conveyor 20 driven by the power unit 45 moves the separated magnetic materials to the lower discharge end 17 of the drum 10 where they are dropped into chute 24 and car 25. The nonmagnetic materials will be moved to the lower discharge end 17 by the constant tumbling due to rotation and gravity where they will be dumped into chute 22 and the car 23.

As seen in FIGURE 3, each magnet 40 is fixed through supporting structure to an arm 48 which is pivoted at pivot 50 to bracket 49 fixed to the exterior surface of the drum. The spring 52 between the bracket 49 and the arm 48 biases the magnet 40 against the exterior surface of the drum 10.

A bracket 52' on each end of magnet 40 carries a cam roller 53 which rides on cam 55 to lift the magnet 40 away from the exterior surface of the drum from the upper part of its orbit on the rotating drum 10 to a short distance down on the downwardly moving side so that the magnetic materials held against the interior surface of the drum will fall away onto the conveyor 20. The cam surface 55 is fixed to plates 56 mounted on suitable framework 58 surrounding the drum. The magnetic influence decreases rapidly with distance from the magnet 40 so that there should be no trouble in causing the magnetic particles to drop from the upper end of the drum onto the conveyor 20. However, if for any reason the magnetic material should cling to the smooth inner surface of the rotating drum 10, the wall 43 on the trough 4-2 adjacent the downwardly moving side of the drum will scrape these particles away. The present magnetic separator is particularly well adapted to the separation of magnetic materials from a mixture of magnetic and non-magnetic materials such as would be found in municipal refuse. As indicated before the mixture is received at the bottom of a vertical elevator 11 which carries it to its upper end by conventional means and dumps it into chute 15. Dust particles which are'preval'ant in the type of mixture described are separated in the dust separator 12. The mixture then is discharged into the inlet end 16 of the rotating drum 10. The drum 10 is rotated by the action of the drive unit 32 indicated by the arrow of FIGURE 2. All of the materials will be carried a short distance upwardly by the upward moving side of the drum 10. The non-magnetic materials will then fall back to the lower portion of the drum and the magnetic materials will be held to the interior wall of drum 10 by the magnet 40 which are biased against the exterior wall by the springs 52. The rotation of the drum 10 provides a thorough turning of the mixture such that all magnetic materials will come in contact with the inner periphery of the drum at some time during the passage of the materials through the drum.

As each magnet 40 reaches the upper end of its orbit on drum 14 the cam rollers 53 will contact the cam surface 55 and be moved away from theexterior surface of the drum thus reducing the magnetic attraction on any magnetic material that is held on the inner periphery thereby causing it to drop away. The magnets material will drop into the trough 42 and be carried away on the conveyor belt 20. Any magnetic materials not removed in this manner will be scraped away by the wall 43 on the trough 42. The springs 52 will cause the magnet 40 to 4 be returned to the outer surface of the drum 10 when cam rollers 53 ride off of the cam surface 55 on the downward side of the rotating drum The magnetic materials will then be conveyed by conveyor belt 2%) to the trough 24 and the car 25 while the non-magnetic materials will be tumbled downwardly by gravity and the rotating drum 10 to the trough 2.2 and the car 23. Additional conveyors.

may be provided at the lower ends of the troughs 22 and 24 as desired in place of the carts.

Two sets of magnets have been shown spaced circumferentially around the outer periphery of the 10. Itwill be understood that any number of sets of magnets 40 may be used on any size of drum 10 without departure from the principle of the invention. Magnets 40 have been shown as permanent magnets. Soft cored magnets utilizing the coil with a separate source oflelectrical power may also be used without departing from the spirit of the invention. It is apparent that the present invention provides a novel magnetic separator which will efiiciently separate the magnetic materials from a mixture of magnetic and non-magnetic materials. The mixture is thoroughly turned during passage through the separator to assure that all the magnetic materials will come in contact with the magnet field producing devices at some time during the passage of the materials through the separators. Separate magnetic fields are provided in circumferentially spaced relation around the separator extending lengthwise to the separator during that portion of the rotation of the separator in which the mixture is turned and these various magnetic fields will be decreased in intensity during a portion of the rotation of the separator to drop the separated magnetic materials into a discharge conveyor to provide a highly effectiveseparating operation. The use of permanent magnets provides for simple economic construction and a long service life.

Having described the details ofmy invention, I claim the following combinations and their equivalents:

1. Apparatus for separating the magnetic materials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic material tubular drum which is open at its opposite ends, support means rotatably supporting the drum in an inclined position, means for rotating the drum around its long'tudinal axis, means for feeding the mixture into the higher end of the drum, discharge conveyor means extending into the drum adjacent the downwardly moving side of the drum, a plurality ofmagnetic field producing means carried in circumferentially spaced relation around the periphery of the drum, each said magnetic field producing means being arranged to produce a separate magnetic field about the drum for attracting magnetic materials in the mixture in the drum and means for moving the magnetic field producing means outwardly from the exterior surface of the drum in the upper half of the downwardly moving side of the drum for dropping the attracted magnetic material into the said discharge conveyor means.

2. Apparatus for separating the magnetic materials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic material tubular drum which is open at its opposite ends, support means rotatably supporting the drum in an inclined position, means for rotating the drum around its longitudinal axis, means for feeding the mixture into the higher end of the drum, discharge conveyor means extending into the drum on an axis parallel with the axis of the drum adjacent to the downwardly moving side of the drum for substantially its entire length, a plurality of magnetic field producing means carried in circumferentially spaced relation around the periphery of the drums each of said magnetic-field producing means arranged to produce a separate magnetic field in the drum for attracting magnetic materials in the mixture in the drum, means for moving'the magneticfield producing means away from the exterior surface the upper half of the downwardly moving sideof the drum for dropping the attracted magnetic materials into the discharge conveyor means.

3. Apparatus for separating the magnetic mate-rials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic material tubular drum which is open at its opposite ends, support means rotatably supporting the drum in an inclined position, means for rotating the drum along its longitudinal axis, means for feeding the mixture into a higher end of the drum, discharge conveyor means extending into the drum parallel to the longitudinal axis of the drum adjacent the downwardly moving side of the drum, a wall extending from one edge of the conveyor to a point adjacent the downwardly moving side of the drum to scrape off magnetic materials which cling to the inside of the downwardly moving side of the drum, a plurality of magnetic field producing means carried in circumferentially spaced relation around the periphery of the drum, each of said magnetic field producing means being arranged to produce a separate magnetic field in the drum for attracting magnetic materials in the mixture in the drum, means for moving the magnetic field producing means radially away from the exterior surface of the drum in the upward half of the downwardly moving side of the drum for dropping the attracted magnetic materials into the conveyor means.

4. Apparatus for separating magnetic materials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic material tubular drum which is open at its opposite ends, support means rotatably supporting the drum in an inclined position, means for rotating the drum around its longitudinal axis, means for feeding the mixture into the higher end of the drum, discharge conveyor means extending into the drum from the lower end for a length substantially equal to that of the drum adjacent the downwardly moving side of the drum, a plurality of magnetic field producing means carried on the exterior surface of the drum in circumferentially spaced relation around the periphery of the drum each of said magnetic field producing means being arranged to produce a separate magnetic field of the drum for attracting magnetic materials in the mixture to the interior periphery of the drum, each said magnetic field producing means being pivoted to the drum, cam roller means fixed to each of the magnetic field producing means, a cam surface adjacent the upper half of the downwardly moving side of the drum in a position to be contacted by each cam roller on each magnetic field producing means so as to move each magnetic field producing means radially away from the exterior surface of the drum in the upper half of the downwardly moving side of the drum for dropping the attracted magnetic materials into the discharged conveyor means.

5. Apparatus for separating magnetic materials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic material tubular drum which is open at its opposite ends, support means for rotatably supporting the drum in an inclined position, means for rotating the drum around its longitudinal axis, means for feeding the mixture into the higher end of the drum, discharge conveyor means extending into the drum adjacent the downwardly moving side of the drum, a plurality of magnetic field producing means carried in circumferentially spaced relation around the exterior periphery of the drum, each of the magnetic field producing means being arranged to produce a separate magnetic field in the drum for attracting magnetic materials in the mixture in the drum, each of the magnetic field producing means having an arm fixed thereto and extending laterally therefrom, pivot means on the exterior surface of the drum pivoted to each of the lateral extending arms fixed to each magnetic field producing means, means to bias the magnetic field producing means against the exterior surface of the drum, cam roller means fixed to each magnetic field producing means, a cam fixed to the supporting structure in such a position so that each cam roller means will contact the cam to. lift the magnetic field producing means radially away from the exterior surface of the rotating drum in the upper half of the downwardly moving side of the drum for dropping the attracted magnetic materials into the discharge conveyor means.

6. Apparatus for separating the magnetic materials from a mixture of magnetic and non-magnetic materials as in claim 1 further comprising dust separating apparatus in the means for feeding mixture into the higher end of the drum.

7. Apparatus for separating the magnetic materials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic tubular drum which is open at its opposite ends, support means rotatably supporting a drum in an inclined position, means for rotating the drum around its longitudinal axis, tubular chute means for feeding the mixture into the higher end of the drum, an

opening in the tubular chute means connected to dust separating means to remove the dust from the mixture of magnetic and non-magnetic materials discharged conveyor means extending into the drum adjacent the downwardly moving side of the drum, a plurality of magnetic field producing means carried in circumferentially spaced relation about the periphery of the drum each side magnetic field producing means being arranged to produce a separate magnetic field around the drum for attracting magnetic materials in the mixture in the drum and means for moving the magnetic field producing means outwardly from the exterior surface of the drum in the upper half of the downwardly moving side of the drum for dropping the attracted magnetic material into the said discharge conveyor means.

8. Apparatus for separating the magnetic materials from a mixture of magnetic and non-magnetic materials comprising a non-magnetic material tubular drum which is open at its opposite ends, support means rotatably supporting the drum in an inclined position, means for rotating the drum around its longitudinal axis, means for feeding the mixture into the higher end of the drum, discharge conveyor means extending into the drum adjacent the downwardly moving side of the drum, a plurality of magnetic field producing means carried in circumferentially spaced relation around the periphery of the drum, each said magnetic field producing means being arranged to produce a separate magnetic field about the drum for attracting magnetic materials in the mixture in the drum and means for moving the magnetic field producing means outwardly from the exterior surface of the drum in the upper half of the downwardly moving side of the drum for dropping the attracted magnetic material into the said discharge conveyor means, means to elevate the mixture to a point above the higher end of the drum, means to connect the means for feeding the mixture into the higher end to the upper end of the elevator means, means connected to the means for feeding the mixture into the higher end of the drum connected to a dust separator for removing dust from the mixture.

Stearns Feb. 8, 1949 Fisher Nov. 24, 1953 

